Datasheet

AD7705/AD7706
Rev. C | Page 14 of 44
TYPICAL PERFORMANCE CHARACTERISTICS
READING NUMBER
32763
0 100
CODE READ
32764
32765
32766
32767
32768
32769
32770
32771
200 300 400 500 600 700 800 900 1000
V
DD
= 5V
V
REF
= 2.5V
GAIN = +128
50Hz UPDATE RATE
T
A
= 25°C
RMS NOISE = 600nV
01166-005
Figure 5. Noise @ Gain = +128 With 50 Hz Update Rate
FREQUENCY (MHz)
0.4
I
DD
(mA)
V
DD
= 3V
T
A
= 25°C
1.2
1.0
0.8
0.6
0.4
0.2
0
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
BUFFERED MODE, GAIN = +128
UNBUFFERED MODE, GAIN = +1
UNBUFFERED MODE, GAIN = +128
BUFFERED MODE, GAIN = +1
01166-006
Figure 6. I
DD
vs. MCLK IN Frequency @ 3 V
GAIN
1
I
DD
(
mA)
1.0
0.8
0.6
0.4
0.2
0
0.1
0.3
0.5
0.7
0.9
2 4 8 16 32 64 128
BUFFERED MODE
f
CLK
= 5MHz,
CLKDIV = 1
UNBUFFERED MODE
f
CLK
= 1MHz,
CLKDIV = 0
V
DD
= 3V
EXTERNAL MCLK
CLKDIS = 1
T
A
= 25°C
BUFFERED MODE
f
CLK
= 2.4576MHz, CLKDIV = 0
UNBUFFERED MODE
f
CLK
= 5MHz, CLKDIV = 1
UNBUFFERED MODE
f
CLK
= 2.84MHz, CLKDIV = 0
BUFFERED MODE
f
CLK
= 1MHz, CLKDIV = 0
01166-007
Figure 7. I
DD
vs. Gain and Clock Frequency @ 3 V
CODE
32764
OCCURRENCE
400
0
32765 32766 32767 32768 32769 32770
300
200
100
01166-008
Figure 8. Histogram of Data in
Figure 5
FREQUENCY (MHz)
0.4
I
DD
(mA)
V
DD
= 5V
T
A
= +25°C
1.2
1.0
0.8
0.6
0.4
0.2
0
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
BUFFERED MODE, GAIN = +128
UNBUFFERED MODE, GAIN = +1
UNBUFFERED MODE, GAIN = +128
BUFFERED MODE, GAIN = +1
01166-009
Figure 9. I
DD
vs. MCLK IN Frequency @ 5 V
GAIN
1
I
DD
(mA)
V
DD
= 5V
EXTERNAL MCLK
CLKDIS = 1
T
A
= 25°C
1.2
0.8
0.6
0.4
0.2
0
1.0
2 4 8 16 32 64 128
BUFFERED MODE
f
CLK
= 5MHz,
CLKDIV = 1
BUFFERED MODE
f
CLK
= 1MHz, CLKDIV = 0
BUFFERED MODE
f
CLK
= 2.4576MHz, CLKDIV = 0
UNBUFFERED MODE
f
CLK
= 2.4576MHz, CLKDIV = 0
UNBUFFERED MODE
f
CLK
= 1MHz,
CLKDIV = 0
UNBUFFERED MODE
f
CLK
= 5MHz, CLKDIV = 1
01166-010
Figure 10. I
DD
vs. Gain and Clock Frequency @ 5 V